The present disclosure relates to single event latchup, and more specifically, to mitigating single event latchup (SEL) in microcontrollers employed in solid state power controllers (SSPC).
Cosmic radiation can induce Single Event Latchup (SEL) in complex electronic devices. In aerospace this may be a particular problem due to higher radiation intensities and system criticality. Certain flight paths have increasing probability of SEL due to global magnetic variances and/or atmospheric conditions. Further, SEL may become more likely at certain polar orientations where cosmic radiation intensity is higher.
Peripheral Interface Controllers (PICs) and other electronic devices are affected by SEL caused by cosmic radiation that interferes with the state of transistors by disrupting charge associated with memory devices or gate control state of a field effect transistor (FET). Solid state power controllers (SSPC) may switch power on and off to electrical loads (e.g., displays, components, etc.). The SSPCs may be controlled by PICs that monitor voltage and current status, and drive field effect transistor gates to turn the power on and off in the load circuits. SEL may cause the transistor gates to shift from their proper state to an erroneous state. Sometimes radiation induced malfunction may be benign because of circuitry design or built-in circuit redundancy. In other cases, radiation may cause a single event upset (a temporary problem that may be recoverable by the system), or a circuit event latch that requires reset of the device. A latchup condition may turn into a burnout condition where excess current burns up the component.
On ground level, SEL causes errors in non-aerospace electronic products in power distribution applications, where non-impacted channels or devices sharing a common power supply with the impacted devices experience diminished power quality. Server farms are also affected by SEL, where latch conditions can cause interruption of service or threaten data persistence. In ground vehicles, SEL can cause vehicle malfunctions in power and electronic control systems.